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For Fossil Hunters, Gobi Is No Desert

UKHAA TOLGOD, Mongolia - On the first afternoon here, fossil hunters struck out across the parched sand to the rock outcrops along the bleached brown ridges and down into the broad basin. They walked their separate courses at paces as if set to geologic time.

With every step, their figures diminished into the expanse of empty silences and far horizons that is the Gobi Desert, where only camels, nomads and hardy paleontologists seem at home.

It has been the paleontologists' boast, never disputed, that this particular forbidding stretch of the Gobi holds the world's richest and most diverse deposits of dinosaur and early mammal remains from 80 million years ago, a critical time for life in the Cretaceous geologic period.

Four years had passed since paleontologists of the American-Mongolian expedition last pitched camp at Ukhaa Tolgod ("brown hills" in Mongolian), scene of their greatest triumphs. They were lured back last month, as surely as gold prospectors to the mother lode, by the expectation that the site has more to yield.

The figures in slow motion appeared indifferent to the baking heat. Each one assumed the prospecting posture: head down, swiveling from side to side, eyes fixed on the ground. At the sight of a fleck of white or an arresting irregularity in the ground, a figure bent for a closer look, then tossed something over the shoulder and wandered on, a common experience in fossil hunting.

The badlands of Ukhaa Tolgod were still generous. Clues in the ground frequently brought the prospectors to their knees. They scraped and dug the hard-packed sand with knife, chisel or geologist's hammer.

If one of them stretched out as if to take a nap, here of all places, it was to apply more delicate strokes and a more discerning eye to the task. This is the discovery posture, and the longer the prone position is maintained, the more likely the hunter will be going back to camp with an exciting find.

Nearly everyone this afternoon had something new to talk about. The haul included two nests of dinosaur eggs, the remains of several ancient lizards and the skull and skeleton of a small mammal, most likely a previously unknown species that lived in the shadow of the formidable dinosaurs.

"Sometimes you go days, whole expeditions, without finding something," said Gina D. Wesley-Hunt, a paleontologist at the Smithsonian Institution. "We found 10 skulls just today, early mammals and lizards."

Happy and relieved by the finds, Michael J. Novacek, a paleontologist at the American Museum of Natural History who has directed the expeditions since their start in 1990, declared, "This place is still rich."

One heard in his words an echo from the celebrated Gobi explorations of Roy Chapman Andrews, also of the American Museum in New York City. At one of the team's first stops, in 1922, a geologist rushed into camp to announce, "The stuff is here."

Andrews put the Gobi on the map as a remote land of fossil wealth with his discoveries and his vivid prose. The desert extends more than 1,500 miles across southern Mongolia and reaches into northwestern China. Russian, Polish and Mongolian scientists made fossil-hunting forays here after World War II. But not until Mongolia declared its independence from the Soviet Union were Americans invited back. In 1993, after three somewhat disappointing seasons, they made their "killer find" here.

In the first three hours, the party extracted from the nearest slopes fossils of 60 dinosaurs, mammals and lizards, an unimaginable rate of one find every three minutes. It was an easy decision to stay another 10 days. In that time, the paleontologists found more dinosaurs -- oviraptors and troodons -- and a virtually complete skull of a Mononychus, which is thought to be a transitional species between dinosaurs and modern birds.

The most poignant discovery was a nest of dinosaur eggs with a broken one exposing a fossilized curled-up embryo. Something never before seen, it is now a museum piece referred to as the embryo on a half shell.

Return visits to Ukhaa Tolgod through 2001 brought other striking finds. Then the scientists decided to give the place a rest and see if a few years of stiff wind and sporadic rain eroded away a fraction of an inch of sand and rock, possibly enough to bring to light more goodies. They were right; there was stuff still here.

Desert Luxuries

In camp that evening, the beer was cold. Under other circumstances, this observation would go without remark. Beer is supposed to be cold, just as the Gobi wind is supposed to kick up the sand, starting in late afternoon, and redistribute it into your tent, your eyes and the food you eat.

But this cold beer had refreshing meaning for Dr. Novacek, who is also vice president and provost at the museum, and Mark A. Norell, the museum's principal dinosaur paleontologist and field leader for all but one of the expedition's 16 seasons. It was a surprise and delight for this reporter.

I had accompanied Dr. Novacek and Dr. Norell for three weeks on their first full season in the Gobi, in the summer of 1991. It was a no-frills reconnaissance for the most part over spine-jarring terrain Andrews and others had never explored.

We did some prospecting in the red sandstone at many places and kept moving camp in constant search of promising dig sites. We had no communications with the outside world. Our rations ran short, and it had been a miscalculation to count on replenishment in the rare settlements we came to. We subsisted mainly on mutton, purchased every few days from any nomad herder we happened on.

And the beer after a hard day fossil hunting was warm, and too soon beer at any temperature was a memory.

I joined this year's expedition with a Times photographer, Chang W. Lee, two officials of the American Museum and a crew shooting a television documentary. I wanted to live again in the harsh grandeur of the Gobi, inspect this treasure-chest fossil site I had heard and written about from afar and see if the grinding field work of paleontology had changed much in the intervening years.

We arrived from Ulan Bator, the capital, by helicopter, a flight of some 500 miles and much more comfortable than the alternative of a three-day journey by truck over rough roads, sometimes no roads at all. The flight took us south of the rolling grasslands into increasingly barren territory. The Gobi itself had not changed.

The land at first is corrugated with low ridges and narrow valleys. Soon, the Altai Mountains in the distance, two ranges running widely parallel east to west, the southern one bordering China, are an ever-present backdrop in subtle tints of vermilion, mauve and khaki.

Farther west, the desert plain between the mountains opens wider and browner. Its flatness is relieved here and there by dry streambeds and gullies, low hills and brown ridges capped with a veneer of gray gravel.

Sand and more gravel are everywhere, and a scattering of dry bush and only infrequent patches of stubby grass being grazed by horses, two-hump Bactrian camels, sheep and goats. It is miles and miles between encampments of gers, the nomads' traditional round, canvas-covered, felt-insulated mobile homes.

Ukhaa Tolgod is about 250 miles southwest of Dalandzadgad, a provincial capital and one of the few towns of any size in the Gobi. The 13-person science party, which had already been in the field working other sites for more than two weeks, had arrived the night before their visitors. The team's yellow tents, a ger and parked trucks stretched out at the foot of a high ridge known as the Camel's Humps.

Dr. Novacek pointed to a large array of solar-energy collectors. The camp had electricity to charge batteries, computers and limited communications and to keep food and beer refrigerated. The expedition had more trucks than before for hauling in gasoline, water, field equipment and an ample supply of food as well as cans of beer.

It was not gracious living, but there were fewer grounds for complaint than on earlier ventures into the Gobi.

An Abundance of Mammals

No one was complaining about anything at the end of the first afternoon's prospecting. The camp buzzed with show-and-tell chatter. Attention centered on Julia Clarke's find, the well-preserved skull and some skeletal bones of a mammal that might have been the size of a small rabbit.

"For a brief moment, I thought it might be a bird," said Dr. Clarke, who teaches paleontology and evolution at North Carolina State University and is a researcher at the North Carolina Museum of Natural History, both in Raleigh. Her specialty is early birds.

"Then I saw the snout and huge teeth," she continued. "Early birds had teeth, but they were not huge. I will keep trying for a bird."

By now, the delicate fossils were laid out on a cloth over the ground. Two men sprawled beside the specimen, repeating the discovery posture. Their faces were inches from the skull that intrigued them.

Guillermo W. Rougier, an Argentine paleontologist on the anatomy faculty at the University of Louisville School of Medicine, held a small magnifying lens to the head and picked at it with an awl. "One of the best skulls we have," he said.

He and Dr. Novacek, lying on the other side, thought it could be a little marsupial, perhaps an ancestor to lineages leading to kangaroos and opossums. If so, it would support the hypothesized Asian origins of the marsupials that eventually migrated to Australia and the Americas.

No, the teeth looked more like those of an early eutherian, ancestors to modern placental mammals, the group that includes humans. Placental mammals bear live young after a prolonged pregnancy. This particular early eutherian occupied the ecological niche of rabbits and had the long hind legs of rabbits and the habits of rodents, but was unrelated to either.

Dr. Rougier began applying gauze and strips of burlap soaked in wet plaster around and over the specimen, preparing it for the trip to a laboratory in something like a broken-leg cast.

"It isn't like anything we've found here before," Dr. Novacek said. "We really won't know what we have until we get it back to the lab."

For every month in the field, paleontologists know from experience, the study of fossils requires at least another 11 months of tedious indoor work back at their universities and museums. But one of the immediately evident changes in Gobi research is the increasing number and variety of small mammals turning up in excavations.

This development is expected to bring new insights into the formative epoch of mammalian life in the Cretaceous Period, which lasted from 140 million years ago until the extinction of nonavian dinosaurs 65 million years ago.

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"When you read some accounts, you would think only dinosaurs lived here in the Gobi," Dr. Novacek said, a while later. "That drives us crazy. The Cretaceous was a fantastic time in Earth history. The world we live in began in the Cretaceous, the modern ecosystem, flowering plants and pollinating insects, the origin of modern mammals."

In the fossil beds at Ukhaa Tolgod, laid down in the late Cretaceous and entombing a broad sampling of its life, not only dinosaurs, paleontologists estimate that over recent years they have found 1,000 mammal skulls. Dr. Novacek said this amounts to 90 percent of all the recovered mammal specimens from the Cretaceous. The beds have also yielded remains of 1,000 lizards. Several of their distant descendants, in sand-colored camouflage, skittered before my steps to the tent in the Gobi night.

The Doctor's Dinosaurs

Next morning, Dr. Norell drove an S.U.V. to the hillside where he had come upon a dinosaur nest the day before. From the slope, he looked over to the saddle between two hills, where in 1993 an expedition truck got stuck in deep sand. The scientists took the mishap as an opportunity and made the first of their findings revealing the site's richness.

Three eggshell fragments on the surface had led Dr. Norell to his new find. The smoothness of the shell, he said, indicated that it was from an egg of a member of the troodontid group of dinosaurs, possibly a Byronosaurus. Digging carefully in the sand, he exposed a nest of broken eggs. The tiny animals had presumably broken open the four-inch-long oval eggs and climbed out. None of their fossils were present, but the paleontologist looked forward to making a detailed study of the shells.

"If you found this anywhere else in the world, you'd be going crazy now," Dr. Norell said, while freeing the nest from the sandstone. "But it takes a lot to top our best stuff, like dinosaurs sitting on top of nests and eggs with embryos, and some other things we have not published on yet."

Later, paleontologists went to examine another nest, one that Dr. Matthew R. Lewin spotted the first afternoon. Dr. Lewin was the expedition physician, a position unheard of in the earliest seasons.

A medical problem brought him to fossil hunting in the last three seasons. For years, some expedition members had complained of persistent fevers, rashes and swollen lymph nodes. Dr. Lewin, an emergency-room doctor and researcher in physiology at the University of California, San Francisco, studied the cases and determined the cause was a tick-transmitted disease, like Rocky Mountain spotted fever, which was readily treatable with antibiotics.

One thing led to another and he signed on as the expedition doctor.

"Finding a nest is really fantastic," Dr. Lewin said, as he and Dr. Norell prepared it for removal. "I saw one shell fragment on the ground. I played the game of hot-and-cold. I walked in one direction. It was cold, no shells. I walked in another direction and saw several shells. I was getting hotter. Digging around, I saw five eggs on top and at least two on the bottom, maybe more."

Dr. Norell identified the physician's fossils as an oviraptor nest, judging by the oval shape and the size of each egg, six to eight inches long, and the shell texture, with its minute ridges.

Oviraptors were carnivores, the top predator in the food chain here. From these eggs they grew to lengths of eight feet, had curved claws and crested skulls and walked, ostrichlike, on their hind legs.

It is a good bet that, on his return to San Francisco, Dr. Lewin will talk more about his oviraptor nest than the few wounds, infections and dehydration cases he treated while in the Gobi.

Sun and Windstorms

Nights in the Gobi are resplendent under the bright arc of the Milky Way and are usually cool, especially here in the high desert, about a mile above sea level. Morning light in summer breaks after 6 a.m. In no time, tents become sweltering saunas and there is nothing to do but emerge into the daylight under an ascending sun.

Add fossil hunters to the list of mad dogs and Englishmen who go out in the noonday sun. Temperatures reach 100 degrees Fahrenheit nearly every summer day and become almost unendurable by late afternoon. There is no natural shade, except in the shadow of a rock face. Yet the scientists went out for several hours each morning, and back again for most of the afternoon, prospecting or excavating.

Without fail, a crew sweated out the heat high on the sandstone cliff of the Camel's Humps. They worked with the full complement of excavation tools: picks and shovels, sledges and chisels, whisk brooms and the ever-handy geologist's rock hammer. Dr. Novacek calls the hand-held tool, with a small pick opposite the hammer head, "the Excalibur of the paleontologist."

The crew usually included Dr. Rougier, Dr. Wesley-Hunt, Pablo Puerta, an Argentine museum technician, and Andres Giallombardo, an Argentine graduate student at the American Museum and Columbia. Bending to their work on a ledge, they extracted two of the five juvenile dinosaur skeletons, which had been left behind, reburied, at the end of a previous visit.

These were ankylosaurs, probably a Pinacosaurus, abundant plant eaters and the prey of predatory dinosaurs. If the juveniles, about 6 to 7 feet long, had lived, they would have grown into 25-foot-long spike-tailed adults.

In late afternoon, dark clouds often move in and the wind picks up. It usually blows fiercely for a couple of hours, testing the stakes and lines of tents and scattering anything not tied or weighted down. A raging sandstorm on my first Gobi trip uprooted my unoccupied tent and sent it bounding several hundred feet across the desert, until we could finally catch up with it.

The scientists with long Gobi experience insisted that the winds now were relatively tame. But one storm persisted longer than usual. The visitors hunkered down in their dining ger, a short distance from the science camp. A separate camp had been set up for the visitors, with amenities supplied by a commercial expedition outfitter.

As the wind shook the ger, those from the plains of middle America got to talking about tornadoes they had weathered. An Oklahoman told an old joke: "You know what a divorce and a tornado have in common? In either case, someone loses a mobile home."

Scientists once thought that violent sandstorms accounted for the number and excellent preservation of fossils hereabouts. The storms buried the animals alive in their tracks and burrows, an act so sudden and devastating that the sand-covered bodies were never scavenged and had undisturbed time for their bones to mineralize as fossils. Now, a more complex natural phenomenon is considered likely.

When a sandstorm is accompanied by torrential rain, which sometimes happens, the water-saturated sand dunes in an earlier time could have collapsed and buried life all around. Scientists suspect this is what killed the juvenile ankylosaurs on the cliff, where the sandstone is the lithified remnant of an ancient dune.

So Ukhaa Tolgod was not only a Cretaceous nursery of nested life, but also a valley of death. Storms fiercer than the one blowing now are what keep paleontologists in business.

Mongolian Hospitality

Dr. Novacek said that next year he wanted the expedition to concentrate on the desert's geology. An effort will be made to date more precisely the age of known sites and establish their temporal relationship to one another. Also, research will be conducted on the minerals in the rocks, determining their oxygen content.

Minerals hold markers of oxygen levels in the atmosphere at the time of their formation. The air today is about 21 percent oxygen. In the Jurassic, the geologic period before the Cretaceous, it was as low as 12 percent, which Dr. Novacek said would have been hard on large animals.

About 100 million years ago, in the middle Cretaceous, the atmospheric oxygen levels started rising, until the present condition was reached 50 million years ago. This could be a factor in the flourishing of mammals after the dinosaur extinction 65 million years ago.

"This is an exciting area of paleontology today," Dr. Novacek said. "We don't know yet how oxygen levels exactly relate to organisms, but this is bringing physical data to bear on life science in studies of biota and ecosystems."

But hunting for other sites for future fossil exploration was on the mind of some of the expedition scientists, who took advantage of the helicopter to make daily scouting runs across the desert.

On one trip, deep in the Nemegt Valley, Julia Clarke descended into a deep canyon. It was good to get out of the hot sun. She scanned the sandstone walls and the ground underfoot. Walking slowly, expectantly, she said she was looking for "any tiny flecks of white, bone fragments that are often bluish white."

Mark Norell scouted a maze of gullies. He spotted the scat of the wild Marco Polo sheep and a set of one's horns. Then the prints of a wolf, a hedgehog and a jerboa, a kangaroo rat. But no fossils. All he could say was, "The Polish worked here years ago and found quite a lot."

Demberelyn Dashzeveg, a 74-year-old paleontologist at the Mongolian Academy of Sciences who has a keen eye for fossils, had more luck in another canyon, known as Zos and only six miles from camp. The geology of the site indicated that this had been an oasis 80 million years ago, the shales and mudstones suggesting there had been standing water. He found bones and teeth of a possible new mammal species.

On the return from a more distant site, Namsrai, the driver (who like most Mongolians uses only his given name), steered the Land Rover with skill and audacity over the rough desert flats, bouncing us up and down and side to side to the Motown music blaring from the tape deck.

We came to a nomad's ger. A black dog guarded the wooden door, but it was friendly enough, as were the two young girls who opened the door and invited us in.

Mongolian nomads are noted for their hospitality. The girls, probably 7 and 8 years old, motioned for us to sit on the stools and cots around the metal stove in the center, its flue rising through an opening at the apex of the domed ger. Hanging on the tent wall, at the back, were equestrian medals the father had won at Nadam, the country's annual festival of horse racing, archery and wrestling.

The girls busied themselves setting out cups and getting a thermos from a cupboard. They poured warm tea with sheep's milk and served a plate of breadsticks. Alice in Wonderland could not have hosted a finer tea party.

The father was out on his horse tending the herds. After a while, the mother appeared. She had been at the only neighboring ger, probably watching television. Solar panels and a satellite dish, also a dirt bike and a pickup, could be seen at the other ger. Some changes in life had come to the Gobi.

Pleasures of Fieldwork

Evenings in camp often end around an open fire, its warmth, the gathering dark and their weariness bringing the scientists together. The treat one evening was pizza. Dr. Clarke prepared the toppings of cheese, tomato sauce, mushrooms and salami -- and the inescapable sprinkling of sand. Dr. Lewin baked the pies in two Dutch ovens over smoldering embers.

Another time, the scientists sat in the sand around a blazing fire, passing a bottle of Genghis Khan vodka for communal swigs. They talked of past discoveries, academic politics back home, memories of hot-water baths and the howling of a wolf they heard the other night. Wolves, heard but not usually seen, are sources of Gobi versions of ghost stories as the campfire burns low.

"Paleontology is not a science rich in money," Dr. Novacek was saying. "Our comforts in the field are limited. But the reality is, we like it that way. We prefer to live a little on the edge."